Technical Abstract:
The bacteria levels of non-washed and washed eggs obtained from caged and cage-free laying hens housed on either all shavings or all wire slat floors were determined. On eight sample days (from 22 to 52 weeks at 4 week intervals), 20 eggs were collected from each pen (n=120/sample day). Ten eggs per pen were washed for 1 min with a commercial egg washing solution (50 C, pH 11), while the remaining 10 eggs were not washed prior to sampling the eggshell and membranes (crush-and-rub) for aerobic bacteria (APC), Escherichia coli (E. coli ), and coliforms. Non-washed eggs produced in an all shavings environment had slightly higher bacteria numbers (APC 4.0 and coliforms 1.1 log10 cfu/mL) than eggs produced on slats (APC 3.6 and coliforms 1.06 log10 cfu/mL), which had significantly higher bacteria numbers than eggs produced in cages (APC 3.1 and coliforms 0.88 log10cfu/mL). Washing significantly reduced APC counts by 1.7 log10 cfu/mL of rinsate, reduced E. coli and coliform counts by only 0.5 log10 cfu/mL of rinsate and the prevalence was reduced from 22.5, 17.5, 12.5% (shavings, slats, and cages, respectively) to 6%. No significant differences were found in APC, E. coli, and coliform counts on eggs from the three housing types following washing.